Q about Apple's new USB-C dongle released this week

MareLuce

macrumors 6502a
Original poster
Sep 26, 2010
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This newly upgraded Apple USB-C dongle is great news for frequent travelers who pack a HDMI cable to watch 4k 60Hz content from their iPad Pro or MBP.
https://9to5mac.com/2019/08/08/new-apple-usb-c-digital-av-multiport-adapter/

Apple this week has quietly released a new version of its USB-C Digital AV Multiport Adapter. This $69 adapter includes a USB-C port, HDMI port, and USB-A port, with the new version making several notable improvements. [...]

The new USB-C Digital AV Multiport Adapter adds support for HDMI 2.0, an upgrade from the original model’s HDMI 1.4b. This means you can now drive 4K 3840 x 2160 video at 60Hz from the following Macs and iPads [...]

I was thrilled till I noticed an article comment of:
>> So the (first of the current generation) 2016 15" MBP is locked out... quelle surprise.

As an alumni of the epic "Waiting for Skylake" 1,477 page MacRumors topic where I held my breath that a Skylake MacBook Pro would be announced "any day now" for 3 years running, of course my current MPB is a 2016 15" flavor.

Any guesses as to why my $4000+ maxed out (2TB, etc...) 2016 MacBook Pro's USB-C port would NOT be supported by that new dongle?

Here's a picture of same dongle, but in the lightning flavor, connected to a TV in a Hong Kong hotel room.



And before anyone says it, yes I realize I don't need 4k @ 60hz to listen to my fave podcasts :).
Switching to podcasts from video makes packing and unpacking go faster.
 

jerryk

macrumors 603
Nov 3, 2011
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SF Bay Area
The first comment in the article you linked implies the hardware in the 2016 MBP can only drive the display at 30Hz when at 4K resolution. This was not an uncommon limitation for 2016, and even occurs today.

60Hz at 4K requires a lot of bandwidth and graphics decoding power.
 
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mroy16

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May 28, 2017
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If I had to guess, I would say that the older MBPs only support the HDMI 1.4 spec natively. In order to get HDMI for 4K@60, you would need to actively adapt the DisplayPort signal to HDMI 2.0. I believe that the adaptor is passive, so it relies on the native HDMI support from your laptop.
 
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MareLuce

macrumors 6502a
Original poster
Sep 26, 2010
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It is supported by the new adapter. You will get 4K output at 30kHz.
Correct.

I meant why would it not support the new capabilities of the USB-C dongle - supporting 4k @ 60Hz.

PS: You said kHz.. Is it Hz or kHz?

If I had to guess, I would say that the older MBPs only support the HDMI 1.4 spec natively. In order to get HDMI for 4K@60, you would need to actively adapt the DisplayPort signal to HDMI 2.0. I believe that the adaptor is passive, so it relies on the native HDMI support from your laptop.
Thank you @mroy16. That sounds logical.

Darn. I wish Apple could fix that with a firmware update.
 

smbu2000

macrumors 6502
Oct 19, 2014
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If I had to guess, I would say that the older MBPs only support the HDMI 1.4 spec natively. In order to get HDMI for 4K@60, you would need to actively adapt the DisplayPort signal to HDMI 2.0. I believe that the adaptor is passive, so it relies on the native HDMI support from your laptop.
That's a good point. I didn't think about the adapter being passive and only using the native HDMI from the computer. They might not have updated the native HDMI spec to 2.0

I've been using a Club3D active usb-c to hdmi 2.0 adapter (supports 4k 60Hz) to connect to my TV since I picked up my 2016 15" MBP in early 2017. The MBP also worked fine on my 4k monitor using a standard usb-c to Displayport cable.

The hdmi port on my older 15" rMBP was also limited to 30Hz at 4K, which is why I used a similar adapter (active mDP to hdmi adapter) to get 4k 60Hz via the TB2/mDP ports.

https://www.club-3d.com/en/detail/2349/usb-3.1-type-c-to-hdmit-2.0-uhd-active-adapter/

If you don't need the usb-a port or the usb-c passthrough (15 MBP has 3 other usb-c ports), then I'd say just get a cable or an active usb-c to hdmi adapter to use for 4k60Hz.
 

joevt

macrumors 65816
Jun 21, 2012
1,418
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Your old Thunderbolt 3 MacBook Pro uses Alpine Ridge which cannot take DisplayPort 1.4 input from AMD graphics. Therefore you are limited to DisplayPort 1.2. The adapter only has two lanes of DisplayPort, so you are limited to 4K 30 Hz.

For 4K 60Hz with this adapter, you need AMD graphics, and Titan Ridge Thunderbolt 3 controllers to output two lanes of DisplayPort 1.4
https://forums.macrumors.com/thread...th-2018-ipad-pro.2191964/page-8#post-27614203

All intel graphics are limited to DisplayPort 1.2.

For your MacBook Pro, you need a four lane DisplayPort 1.4 to HDMI 2.0 adapter.
https://www.club-3d.com/en/detail/2442/displayport_1.4_to_hdmi_2.0b_hdr/
DisplayPort 1.4 is required for HDR but you should be able to get at least 4K 60Hz without HDR.

I don't know if Alpine Ridge is limited to DisplayPort 1.2, or if it's just limited to HBR2 speeds (5.4 Gbps per lane). If the latter, then maybe you can get DisplayPort 1.4 HDR from your AMD graphics through the Alpine Ridge since only 5.4 Gbps is required.
 

joevt

macrumors 65816
Jun 21, 2012
1,418
688
Apple lists the following as supporting 4K 60Hz:

iPad Pro 11-inch
iPad Pro 12.9-inch (3rd Generation)
MacBook Pro (15-inch, 2017 and later)
iMac (Retina 5K, 27-inch, 2017 and later)
iMac (Retina 4K, 21.5-inch, 2017 and later)
iMac Pro (2018)

Don't some of those still only have Alpine Ridge and therefore only support DisplayPort 1.2?
2018 MacBook Pros and 2018 Mac minis have Titan Ridge (but Mac mini only has Intel graphics).
I believe all the Macs from 2017 use Alpine Ridge.
I believe the iMac Pro (2018) still uses Alpine Ridge.

I would like to hear from anyone with a Mac from the above list that has Alpine Ridge and this adapter.
 
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